skim {scope} | R Documentation |
Apply a function to values in the specified data frame column, across each group of rows specified in the scope object.
skim(x, this, FUN = "max", scope = NULL, ...)
x |
A data frame. |
this |
A column name in x , the main argument to FUN . |
FUN |
An aggregate function. |
scope |
A scope object, e.g. created by scope() . |
... |
Extra arguments to pass to FUN . |
The default scope is all rows. The default function is max(...)
.
Remember that skim()
returns a data vector, not a scope object. For
functions that return one of their arguments (perhaps max
and min
but perhaps
not mean
) the result of skim()
can be passed back to scope()
to ‘probe’ for
the row from which the value originated. There is a danger that more or fewer
than one row will be detected, so check with score()
.
A vector of same length as this
giving aggregated values.
data(Theoph) #What is the maximum concentration for each subject? S <- scope(Theoph,'Subject') m <- skim(Theoph,'conc',scope=S)